Catheter associated urinary tract infections (CAUTIs) are a common problem for those with indwelling urinary catheters. It is observed that over 70% of urinary catheters become colonized with bacteria over a relatively short period of time. Bacteria colonization is often accompanied by the formation of a biofilm that is known to sustain bacterial growth and to also increase the likelihood of infection.
Various approaches have been employed to reduce urinary tract infections associated with the use of indwelling urinary catheters. Common interventions such as silver alloy coatings, antimicrobial catheter coatings, hydrophilic catheters, ureteral stents, use of sealed catheter-tube junctions, and anti-infective bladder irrigation have yielded inconsistent results in reducing the incidence of CAUTI. The deficiencies associated with these and other common interventions are especially troubling in light of the emergence of antimicrobial-resistant organisms such as multi-drug resistant (MDR) organisms which are becoming more prevalent.
Ultraviolet (UV) irradiation has long been recognized for its potential to destroy viruses, bacteria, fungi, and other harmful microorganisms. Application of UV radiation is known to sever carbon-carbon double bonds in genetically-relevant organic moieties (e.g., pyrimidines, purines and flavanoids). Susceptibility to UV irradiation occurs when dimers (uracil and cytosine in ribonucleic acid, RNA, and thymine and cytosine in deoxyribonucleic acid, DNA) are formed.
Based upon this finding, some catheter devices have been designed to allow in situ sterilization of catheter elements and surrounding tissues by transmitting UV radiation through indwelling elements. Arcand et al. (WO 2010/132429), for example, describes an elongated catheter insertion device that includes an integrated UV sterilization assembly providing both inward-directed (toward the interior of the device) and outward-directed (toward the exterior of the device into surrounding tissue) UV irradiation. Such a device does not penetrate far into the subject's body, and is intended to irradiate an instrument, such as a needle or catheter, as the instrument passes through the device. In another example Kaldany (U.S. Pat. No. 5,695,482) describes catheter tubes capable of in situ UV sterilization in which linear fiber optics embedded in walls of a catheter tube allow multi-directional UV radiation of both the catheter interior and the surrounding tissue.
Common forms of UV radiation known to destroy harmful microorganisms include UVA (315 to 400 nm), UVB (280 to 315 nm) and UVC (100 to 280 nm) radiation. However, all forms of UV light can also produce DNA damage in mammalian cells and are potentially harmful to the tissues being penetrated by the catheter. A clear link exists between chronic exposure to UV light and skin cancer resulting from UV-induced damage to DNA.